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Subject: Re: [PATCH] KVM: X86: Fix the decoding of segment overrides in 64bit
 mode
To:     Andrew Cooper <andrew.cooper3@citrix.com>,
        Wanpeng Li <kernellwp@gmail.com>, linux-kernel@vger.kernel.org,
        kvm@vger.kernel.org
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From:   Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <9bd82cb0-d88f-4891-a111-3704802e1d4e@redhat.com>
Date:   Thu, 22 Mar 2018 13:38:05 +0100
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On 22/03/2018 12:04, Andrew Cooper wrote:
> We've got a Force Emulation Prefix (ud2a; .ascii "xen") for doing
> magic.  Originally, this was used for PV guests to explicitly request an
> emulated CPUID, but I extended it to HVM guests for "emulate the next
> instruction", after we had some guest user => guest kernel privilege
> escalations because of incorrect emulation.

Wanpeng, why don't you add it behind a new kvm module parameter? :)

Paolo